In the second phase, The Ancestor summons Absolute Nothingness, which has a extremely high dodge-rate but can't attack, effectively making a obstacle. If you kill enough of the Imperfect Reflections, you should end the first phase. The first form also has Time Heals All, a healing move. However, he sometimes summons a Imperfect Reflection, which damages him when killed. This first form is immune to all damage, and will summon Perfect Reflections of himself to attack you.

In the first phase of his fight, the Ancestor attacks you, with it being unknown if this is a illusion or truly him trying to kill you. ~ The Ancestor as he engages the heroes in battle at the heart of the world. You still foolishly consider yourself an entity separate from the whole. If this happened, humanity likely would not survive. It is strongly implied that the Comet is a sort of incubator for an unborn member of its species, and that if it were to hatch and mature, it and the Heart would battle for dominance of the world. While this doesn't debunk its claim to have created humanity, the revelation throws much of what it says in doubt. In the Color of Madness DLC it is revealed that its claims of godhood are lies, and it is, in fact, one of a race of similar beings. Beating it will cost two of your hero's lives and will not be easy, and even when you win, the ending seems to hint that either the Heart of Darkness traps The Hamlet in a endless cycle of misery or you revive it yourself in the future, seemingly trapping the world in a time loop. Here, there's only one path to take and only one goal: Defeat the Heart of Darkness. It is fought during the last mission of the area, being called Hell is in the Heart. The Heart of Darkness can be fought inside the titular Darkest Dungeon, the final challenge and area of the game. The cultists and dark priests who worshiped became warped due to it, become partially elderitch. Responsible for the corruption of the Hamlet, it manifested through the evil of your ancestor, causing the man to become it's vessel.

Possibly disguised as the Ancestor, the Heart of Darkness is the possible creator of humanity and the representation of the Ancestor's desires.

The darkest dungeon final boss